The invention relates to compositions and to methods of preventing and treating diseases such as proliferative disorders, viral infections and neoplastic growth and metastasis with the compositions.
Continuous proliferation of tumor cells is a primary requirement for malignancy. It has been disclosed that most cancers are ultimately lethal because of their ability to metastasize and form tumors at secondary sites (Nicolson, G. L., Biochem. Biophys. Acta. 695: 113, 1982; Poste, G. and Fidler, I. J. Nature 283: 139, 1980; and Weiss, L., Semin. Oncl. 4: 5-19, 1977). Therefore, there is a need for drugs or biological response modifiers capable of inhibiting both metastasis as well as tumor cell proliferation. In this regard, it has been disclosed that certain glycoconjugate structures found on the tumor cell surface contribute directly to the manifestation of the metastatic phenotype. (Nicolson, G. L., Biochem. Biophys. Acta (695: 113, 1982).
Previous work done by the inventor and others has indicated that modification of Asn-linked carbohydrates on malignant cells reduces metastatic potential. (Dennis, J. W. et al Nature 292: 242, 1981; Dennis, J. W. et al. J. Cell Biol. 99: 1034, 1984; Dennis, J. W. J. Natl. Cancer Inst. 74: 1111, 1985; Takasai, S., et al, Biochem. Biophys. Res. Commun. 92: 7365-742, 1980). For a number of murine tumor cell lines it has been shown that sialylation of available cell surface galactose and N-acetylgalactosamine enhances metastatic potential. (Yogeswarren, G., and Salk, P. L., Science (Washington DC), 1514-1516, 1981). It has also been shown that loss of sialylated Asn-linked oligosaccharides in lectin resistant mutants of the B16 melanoma and the MDAY-D2 tumor cell lines decreases metastatic potential (Finne, J. et al. Cancer Res., 40: 2580-2587, 1980; Dennis et al, J. Cell. Biol. 99: 1034-1044, 1984.). In addition, the inventor has shown that loss of these structures reduces the growth rate of the tumor cells in situ. (Kerbel, R. S., Dennis, J. W. et al, Cancer Mestastasis Reviews 1, 99, 1982).
Malignant transformation of murine and human cells often leads to increased branching of Asn-linked oligosaccharides (Yamashita K. et al., J. Biol. Chem. 259, 10834, 1984; Pierce M. and Arango J., J. Biol. Chem. 261, 10772, 1986; Debray H. et al., Int. J. Cancer 37, 607, 1986) and this in turn may increase the sialic acid levels in the glycoconjugates. Recent work done by the inventor has shown that increased branching is not directly related to the transformed phenotype but can occur subsequently as a result of a secondary change in gene expression. Most importantly, increased branching of Asn-linked oligosaccharides was shown by the inventor to be directly related to metastatic potential of the tumor cells (Dennis J. W. et al., Science, 1987), and may also endow the tumor cells with a selection growth advantage in vivo. (Kerbel R. S. et al, Proc. Natl Acad. Sci. U.S.A., 84, 1263, 1987).
Swainsonine (SW) is found in spotted locoweed and when ingested by domestic farm animals, the compound inhibits lysosomal mannosidase as well as Golgi .alpha.-mannosidase II (Molyneux, R. J. and James, L. F., Science (Washington DC) 216: 190-191, 1981; Tulisani, D. R. P. et al. J. Biol. Chem. 257: 7936-7939, 1982). The brain tissues accumulate lysosomal vesicles containing oligomannose structures similar to that observed in hereditary lysosomal storage diseases. There are a number of tissue-specific mannosidases, and it has been found that rodents have a brain enzyme that is not inhibited by swainsonine (Tulsiani, D. R. P. and Touster, O., J. Biol. Chem. 260: 13081-13087, 1985). In addition, it has been found that rat brain does not accumulate oligomannose structures and the animals do not show neurological symptoms when fed the compound. (Tulsiani, D. R. P. et al. Arch. Biochem Biophys. 232: 76-85, 1984). Most significantly, it has been found that Swainsonine blocks branching of Asn-linked oligossacharides by competatively inhibiting the golgi processing enzyme .alpha.-mannosidase II (Tulsioni, D. R. P., J. Biol Chem 258, 7578, 1983).
Humphries et al. (Proc. Natl. Acad. Sci. USA 83: 1752-2756, 1986), have found that treatment of B16F10 murine melanoma cells with swainsonine inhibits their ability to colonize the lungs of C57BL/6 mice after intravenous injection of the B16F10 cells. However, the treatment was found to have no effect on B16F10 viability or on tumorigenicity after subcutaneous implantation. In the study swainsonine was not administered to tumor-bearing mice.
Tunicamycin, is an antibiotic produced by Streptomyces lysosuperficus, and it has been found to inhibit the first step in the formation of Asn-linked oligosaccharide chains (Keeler, R. K. et al., Biochem. 18: 3946-3952, 1979). It has been shown that B16 melanoma cells grown overnight in tunicamycin are less efficient at lung colonization (Irimura et al., Cancer Res. 41, 3411-3418, 1981). However, tunicamycin causes gross disfunction of glycoprotein localization and function in the cell (Gibson R. et al., Trends in Biochem. Sci. Nov. 290-293, 1980) and thus has been found to be toxic for many cell types (Crisuodo, B. A. and S. S. Krag, J. Cell Biol. 94: 586-591, 1982).
Interferons are proteins secreted by animal cells in response to viruses as well as growth factors (Zullo, Z. N., et al., Cell 43: 793, 1985). Interferon binds to a cell surface receptor and manifests a number of biological responses including antiviral effects and inhibition of cell growth (S. L. Lin et al., Science 233: 356-358, 1986).
Interferon has been shown to reduce the expression of the c-myc oncogene in human cell lines (Einat M. et al., Nature 313, 597, 1985), c-myc is one of the cellular genes that is actively transcribed in cells stimulated to proliferate (Lau L. F. and Nathans D., Proc. Natl. Acad. Sci. USA 84, 1182, 1987) and is through to be required for cell proliferation (Whitfield J. F. et al., Cancer and Metastasis Reviews 5, 205, 1987). As such, the level of c-myc mRNA in cells can be used as an indicator of the cells growth state.
Interferons have been used in clinical trials for the treatment of most types of cancer (Goldstein, D., and Lasglo, J., Can. Res. 46: 4315, 1986). Significant response rates to interferons have been observed with hairy cell leukemia and lymphomas, while other tumor types have been found to be less responsive. High concentrations of interferon are often required and this has life threatening side effects, for example, hypotension and renal failure (Levine A. S. et al., Can. res. 39: 1645-1650, 1979).
A number of inducers of interferon have been disclosed. Polyinocinic, polycytidylic acid (Poly (I.C.)), a synthetic double-standed RNA is an effective inducer of interferon in vitro and in vivo. Poly (I.C.)-lysine (poly (I.C.).LC) is more stable in humans than poly (I.C.) and it has been used in clinical studies (Levine, A. S. et al., Cancer Res. 39: 1645-1650). T. Hunter (Nature 322: 14-16, 1986) has reviewed other inducers of interferon, namely transforming growth factor (TGF-.beta.) and tumor necrosis factor (TNF).
It has been found that tunicamycin enhances the antiviral effects of interferon on enveloped viruses and enhances the antiproliferative effect of interferon on 3T3 fibroblasts (Moheshwari, R. K. et al., Science 219: 1339-1341, 1983). Tunicamycin has not been used clinically due to its toxicity (Morin, M. J. et al., Can. Res. 43: 1669-1674, 1983).